Selective Bond Dissociation and Rearrangement with Optimally Tailored, Strong-Field Laser Pulses

Abstract

We used strong-field laser pulses that were tailored with closed-loop optimal control to govern specified chemical dissociation and reactivity channels in a series of organic molecules. Selective cleavage and rearrangement of chemical bonds having dissociation energies up to approximately 100 kilocalories per mole (about 4 electron volts) are reported for polyatomic molecules, including (CH₃)₂CO (acetone), CH₃COCF₃ (trifluoroacetone), and C₆H₅COCH₃ (acetophenone). Control over the formation of CH₃CO from (CH₃)₂CO, CF₃ (or CH₃) from CH₃COCF₃, and C₆H₅CH₃ (toluene) from C₆H₅COCH₃ was observed with high selectivity. Strong-field control appears to have generic applicability for manipulating molecular reactivity because the tailored intense laser fields (about 10¹³ watts per square centimeter) can dynamically Stark shift many excited states into resonance, and consequently, the method is not confined by resonant spectral restrictions found in the perturbative (weak-field) regime.